A father reacts after the death of two of his children, whom activists said were killed by shelling by regime forces in Aleppo. Photo: Reuters

The Observatory said at least 12 bodies were recovered, several of them rebels.

The Local Coordination Committees, a grassroots network of activists, estimated that at least 50 people died in the attack.

The Observatory said 160 people were killed in violence across Syria on Thursday, including 72 civilians, almost half of whom were women and children.

On the humanitarian front, a 33-truck aid convoy organised by Turkish and Qatari relief groups left Istanbul on Thursday carrying 850 tonnes of flour.

‘‘[The] regime is bombing the bakeries and there is a very huge need for flour in Syria,’’ Huseyin Oruc, the vice-president of the Turkish IHH Humanitarian Relief Foundation, said.

One of Syrian President Bashar al-Assad’s main allies, Hassan Nasrallah, chief of the Shiite militia Hezbollah in neighbouring Lebanon, warned in a televised speech on Thursday that Syria was threatened with ‘‘schemes of division and partition’’.